power-internal: Exclude only device_power_get_wakeup_reason() on a specific profile

power-internal: Exclude only device_power_get_wakeup_reason() on a specific profile

The previous patch(733acf) excludes the whole power-internal.c/.h when
they are built on a specific build envrionment. In such case, however,
there were other pakages dependent on the power-internal.c/.h, making
build error. Thus, instead of excluding the whole power-internal.c/.h,
exclude only the function device_power_get_wakeup_reason() from building.

Change-Id: Ib7474394246cf2d4e48b9ca312546f1970348ce9
Signed-off-by: Youngjae Cho <y0.cho@samsung.com>